Finally the bug is solved. you can get and set items on wikidata via PWB
At first you must define a wikidataPage and these are methods you can
use. I'll try to expand and make more methods but i don't know any and
your help will be very useful:
Supports the same interface as Page, with the following added methods:
setitem : Setting item(s) on a page
getentity : Getting item(s) of a page
these examples worked for me:
site=wikipedia.getSite('wikidata',fam='wikidata')
page=wikipedia.wikidataPage(site,"Helium")
text=page.getentity()
page.setitem(summary=u"BOT: TESTING FOO",items={'type':u'item',
'label':'fa', 'value':'OK'})
page.setitem(summary=u"BOT: TESTING
GOO",items={'type':u'description',
'language':'en', 'value':'OK'})
page.setitem(summary=u"BOT: TESTING
BOO",items={'type':u'sitelink',
'site':'de', 'title':'BAR'})
Cheers!
--
Amir